Some analysts are calling a top for the dollar

After a stunning rally of over 20% from mid-2014 through this March, the US dollar index (which measures the dollar against a basket of other major currencies) has slowed its run.

And in a note to clients on Tuesday, UBS analysts Michael Riesner and Marc Müller declared that there's a "major tactical US dollar top in place".

They wrote, "Strategically, we called a US Dollar bull market last year and it was and remains our view that, apart from tactical corrections, the Dollar bull market will continue into H2 2016 ... Tactically, and on track with our cyclical model, we saw a big reversal in the US Dollar over the last 2 weeks."

They based their analysis on their proprietary advance/decline line, a charting tool that technical analysts use to measure the number of stocks (or, in this case, currencies) that are moving higher versus those declining. And the analysts' advance/decline line for the dollar, which measures it against 20 currencies, reversed course two weeks ago. UBS The dollar is now set to drop for a third straight week.

And a Bloomberg report highlighted something else that technical analysis is saying about the dollar: It has formed a dreaded death cross.

That happens when the 50-day moving average crosses below the 200-day moving average. Basically, technical analysts take it as a bearish sign and a reversal of the currency's long-term trend.

In the chart below, the blue line is the 50-day moving average, while the red line is the 200-day.

According to Bloomberg, a death cross hasn't happened to the dollar since September 2013. Investing.com, Business Insider